Piezoelectric Oscillator Layout to Prevent Adhesive Pad Contamination
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Solution Overview
Problem
In piezoelectric oscillators, the adhesive used for bonding between the substrate and the IC chip can run over, contaminating the pad on the substrate, making it difficult to bond wires, and increasing the size of the device due to the need for longer distances between components.
Innovation Solution
A vibrator device design featuring a semiconductor element flip-chip mounted on a base with a vibrator mounted via an adhesive, using coupling wires and bumps for electrical coupling, and a mold portion to cover the semiconductor element and vibrator, allowing for shorter distances between components and reduced adhesive deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is applied to bond the semiconductor element to the base, then bonding strength is improved, but adhesive may run over and contaminate the pad, making wire bonding difficult
Solution Approach 1:
The pad is extracted from the base and relocated to the semiconductor element, separating the bonding area from the electrical connection area. This prevents adhesive run-over from contaminating the pad while maintaining strong bonding between the semiconductor element and base through bumps at the original base location.
Solution Approach 2:
Bumps serve as intermediaries for electrical connection between the base and semiconductor element, replacing the traditional pad-wire bonding structure. This eliminates the need for a exposed pad on the base that could be contaminated by adhesive, while still providing reliable electrical connectivity.
2Object-generated harmful factors
If the distance between the end portion of the semiconductor element and the pad is increased to prevent contamination, then adhesive run-over is avoided, but the device size increases
Solution Approach 1:
Instead of increasing the distance between the semiconductor element end and pad to prevent contamination, the invention inverts the traditional structure by placing the pad on the semiconductor element rather than the base. This allows the pad to be positioned immediately adjacent to the semiconductor element end without contamination risk, enabling compact device design.
3Reliability
If wire bonding is used to connect the pad, then electrical connection is established, but the process becomes complex and time-consuming
Solution Approach 1:
The bonding structure is merged and simplified by using bumps that simultaneously provide mechanical support and electrical connection between the base and semiconductor element. This eliminates the need for separate wire bonding processes, reducing manufacturing complexity and time while maintaining reliable electrical connectivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enables further downsizing of the vibrator device while maintaining reliable electrical connections and reducing parasitic capacitances, resulting in improved frequency-power characteristics.
Implementation Method 1
a piezoelectric vibrator and an IC chip as a circuit oscillating the piezoelectric vibrator
Implementation Method 2
a vibrator mounted on the semiconductor element via an adhesive
Data Source
AI summary
A vibrator device includes a base, a semiconductor element, and a vibrator. The semiconductor element is flip-chip mounted on the base, the vibrator is mounted on the semiconductor element via an adhesive, a first coupling wire is formed on the base, the semiconductor element and the first coupling wire are electrically coupled via a first bump, the first coupling wire and the vibrator are electrically coupled via a first wire, and the semiconductor element and the vibrator are covered by a mold portion placed on the base.